Distraction device for maxillofacial surgery

ABSTRACT

The invention relates to a device that may be used in maxillofacial surgery and dentistry. The device comprises a translating bracket with a cylinder and a fixed bracket with a chamber. A distraction screw is mounted through the cylinder and with one end resting on the chamber. By turning this screw when the device has been mounted on bone pieces osteogenesis can be achieved. The device can be made suitable for both dentulous and edentulous patients with alveolar defects.

BACKGROUND OF THE INVENTION

[0001] Distraction Osteogenesis has been used in the facial skeletonfollowing the principles laid down by Codvilla in 1905 and Ilizarov in1952. McCarthy first introduced distraction osteogenesis in the mandible(lower jaw). Several distraction devices have been disclosed in the art.

[0002] McCarthy discloses in “Distraction of the craniofacial skeleton”(Springer Verlag, pages 68, 88, and 89; 1999) three extra-oralhorizontal uniplanar and multiplanar distractors. The uniplanardistractors have two pin clamps, a distraction screw, and fourpercutaneous pins. The pins are of fixed length and about 80 mm long ofwhich about 20 mm is fixed into the bone and 60 mm extends out of thebone. The diameter of the pin is between 10-15 mm in diameter. Thedistractor is placed percutaneously (through the skin of the face). Thedevice is large, has a complex screw, and requires fixation through theskin with long pins. Therefore, fixation and removal needs to beperformed under general anesthesia. McCarthy further describes twogeneral drawings of intra-oral horizontal uniplanar distractors on page98 and 99. On page 223, McCarthy discloses FIGS. 7.4 and 7.5 with twobulky intra-oral distractors with two guiding rails. FIG. 7.4 disclosesa device with a distraction screw of about 3 cm long and a diameterlarger than about 5 mm. The uniplanar distractor has two translatingbrackets, moving in opposite directions and no fixed bracket. All piecesare welded or soldered together. The device is large and complex andrequires transmucosal fixation. FIG. 7.5 discloses a distraction screwof about 40 mm long and a diameter of about 6 mm The right fixed bracketis about 25 mmm long, about 40 mm wide and about 8 mm thick. The left,translating bracket is about 40 m wide. The prominent interconnectingbars are positioned on top of the guiding rails. All pieces are weldedor soldered together. The device is large and complex and requirestransmucosal fixation

[0003] Unidirectional distraction devices with the numbers 51-500-10,51-500-15 and 51-500-20 by Martin, comprise each 2 guiding rails, afixed bracket, a translating bracket, 1 distraction screw, 6osteosynthesis pins and 1 or more cranks. The distractor requires aninterconnecting bar between the guiding rails. This distractor is largeand requires a complex surgical operation for fixation and removal undergeneral anesthesia.

[0004] Dyna Form is marketed and is an intraoral distraction system forwidening of the jaw. It consists of a translating bracket with acylinder, a distraction screw, a fixed bracket that extends above thetranslating bracket, two guiding rails, and pins. The distraction screwpushes against the extension of the fixed bracket. Size and constructionof the device make it too bulky to be used in vertical alveolardistraction.

[0005] Jaw lengthening distraction devices with numbers 51-525-06,51-525-09, 51-525-12 and 51-525-15 by Martin, each comprises a fixedbracket with up to 14 perforations, a translating bracket with acylinder and up to 10 perforations, and 1 chamber. The chamber ispartially hollow and contains the entire length of a distraction screw,except for the head. The chamber contains the cylinder of thetranslating bracket. The use of many lateral pins could lead to damageto adjacent anatomical structures. The use of a lengthy and bulkychamber with cylinder may be uncomfortable during the period ofdistraction and are too large for use in vertical alveolar distraction.Further, it seems that the distraction screw cannot be replaced with analternative distraction screw without removal of one or more of thebrackets. Similar devices have been described in DE 297 16 635 and aremarketed by Synthes.

[0006] A vertical alveolar distractor by Stryker Leibinger comprises atranslating bracket, a fixed bracket, 10 to 20 perforations in total,and one distraction screw and was presented at a conference in Paris, inJune 1999. One perforation in the translating bracket is used as acylinder for the distraction screw. The brackets are relatively thick.Some of the perforations are positioned in the distraction gap andinterfere with the neo-osteogenic site. The use of many lateral pinscould lead to damage to adjacent anatomical structures. U.S. Pat. No.5,769,850 (Chin) describes a device for vertical alveolar distractionosteogenesis containing a translating upper bracket with a cylinder, afixed bracket with a chamber, a distraction screw, and pins. Thedistraction screw has one or more sharp ends. It is required to drill ahole in the bone to allow for rotation of the screw end within the 3osseous segments. The device has sharp edges, does not have a smoothsurface and extends into the osteogenesis site. The pins are screwedthrough the bracket towards the distraction screw. The device does nothave a guiding rail and has a chamber, which is short in length. Similardevices are sold under the Lead System trademark name.

[0007] JP 10043203 (Keisei Ika) describes 2 types of devices: one devicewith a connection between the jaw and the cranium for extending the jawaway from the cranium and another device with two connections to the jawfor lengthening the ascending ramus of the mandible (=lower jaw). Thedevices contain a translating bracket (plate) with a cylinder, a fixedbracket with a chamber with an aperture (hole), and a distraction screw.The device extends (distracts) the ascending ramus of the mandible awayfrom the cranium, uses pins and has a thin chamber. Devices useextensions into the site of osteogenesis. The devices have sharp edges,particularly the end of the screw and the brackets, and do not have asmooth surface. The prominent and sharp edges of the plate face awayfrom the underlying jaw bone towards and into the soft tissues. Deviceshave extensions into the site of osteogenesis. None of the devices has aguiding rail. Devices are large with sizes of up to 100 mm and more,which is too large to be used for vertical alveolar distraction.Further, the pins are not threaded.

[0008] U.S. Pat. No. 5,895,387 (Guerrero) describes a distraction devicefor lengthening the jaw and for extending the cranium. The device has atranslating bracket with a cylinder, a fixed bracket, and pins. However,the device has a large size and is not described for vertical alveolardistraction. Guerrero uses an anvil area and does not have an aperturein the chamber. The device does not have a guiding rail. The device hassharp edges instead of a smooth surface. In fact, it has “clamps” thatextend into the site of osteogenesis.

[0009] U.S. Pat. No. 5,980,252 (Samchukov) describes a tooth bornealveolar distraction device containing a translating bracket withcylinder, a distraction screw, and a fixed bracket. The device does nothave pins and does not have a guiding rail. The device has sharp edgesand extensions into the site of osteogenesis. The distraction screw doesnot push against the chamber and the screw cannot easily be replacedduring the distraction.

[0010] DE 298 13 087 (Karl Leibinger) describes a distraction devicecontaining a translating bracket with a cylinder, a distraction screw, afixed bracket and pins. The device has 2 guiding rails on the side ofthe screw to add to the stability while extending the length of the jaw.However, the fixed bracket does not have an aperture and the deviceseems too bulky for vertical alveolar distraction.

[0011] Surprisingly, we have found that one or more problems of thedistractors of the prior art can be overcome by using the distractordevice of the present invention.

INVENTION

[0012] The invention relates to a device comprising two or morebrackets, and a distraction screw. Preferably, the device compriseslateral pins. Optionally, the device comprises one or more guidingrails. Optionally, the device comprises an interconnecting bar connectedwith another device.

[0013] The invention preferably relates to a vertical alveolarosteogenic microdistractor device comprising a translating bracket witha cylinder, a fixed bracket with a chamber with an aperture, adistraction screw, and lateral pins characterized in that the devicedoes not interfere with the osteogenic side. Preferably, the inventionrelates to a device, wherein the device is smooth and without sharpedges. Preferably, the invention relates to a device wherein thebrackets do not have extensions that are directed perpendicularly to thedistraction screw and perpendicularly to the brackets, at a levelbetween the brackets and directed away from the distraction screw intothe site of osteogenesis. Preferably, the invention relates to a devicewherein the device comprises a guiding rail and/or an interconnectingbar. Preferably, the invention relates to a device wherein thedistraction screw is replaceable.

[0014] A preferred embodiment of the invention is a distractor composedof four parts, including two brackets, the vertical screw, four titaniumlateral (osteosynthetic) pins. The present invention further relates toa device comprising a translating bracket. with a cylinder, a fixedbracket with a chamber with an aperture, a distraction screw, andlateral pins for use in vertical alveolar osteogenesis. The presentinvention further relates to a method of manufacturing a devicecomprising a translating bracket with a cylinder, a fixed bracket, aguiding rail, and a distraction screw, wherein the guiding rail slidesthrough the translating bracket, and wherein the distraction screw isturned through the cylinder and placed into the aperture of the chamberof the fixed bracket.

[0015] The present invention further relates to a method of verticalalveolar distraction of two bone pieces using a device comprising atranslating bracket with a cylinder, a fixed bracket with a chamber withan aperture, and a distraction screw wherein the fixed bracket isconnected to one piece of bone, the translating bracket is connected tothe other piece of bone, the distraction screw is inserted through thecylinder of the translating bracket and placed in the aperture of thechamber of the fixed bracket, wherein the two pieces of bone aredistracted by turning the distraction screw, and wherein the device doesnot interfere with the neo-osteogenic site.

[0016] The present invention further relates to a fixed bracketcomprising a chamber and perforations and to the manufacture thereof Thepresent invention further relates to a translating bracket comprising acylinder and perforations and to the manufacture thereof

FURTHER ADVANTAGES

[0017] The dimensions of the device are suitable and tailored todistraction histioosteogenesis in the resorbed and atrophied orofacialosseous skeleton. With the design of the device an attempt is made toprovide for all parameters affecting distraction osteogenesis, forinstance in patients with the edentulous mandible and/or maxilla jaws,and dentulous (tooth bearing) patients with alveolar defects. Thesimplicity and the size of the device make it easily applicable and moresuited in the oral cavity and in the orofacial skeleton.

[0018] The device of the present invention has further advantages overthe prior art. The device is small without any internal empty space(this may be called an “open structure”). Its small size allows forimplantation underneath the mucosa, under the mucoperiosteal layer. Thesmall size further leaves little scar tissue after distraction.

[0019] The design of the device allows for placement and removal througha simple surgical procedure, without the requirement for generalanesthesia of the patient. The size and design of the device presentedenables the surgeon to use a minimally invasive surgical approach whenplacing the device. The design avoids interference with the site ofneo-osteogenesis. The device is further designed such that it produceslittle or no inconvenience or irritation for the patient during theperiod of distraction. Furthermore, a preferred embodiment of the deviceof the invention allows for changing the distraction screw withoutremoval of the brackets. The design of the device makes the chance ofinfections and other complications particularly small. As a consequenceof the design, the device has high rigidity, potentially leading tofewer complications than the devices of the prior art. The design avoidsmicro movements at the site of neo-osteogenesis.

[0020] The design of the device accommodates for the specific featuresof the tight mucoperiosteal layer. In order to protect thismucoperiosteal layer under which the device is to be inserted:

[0021] (i) the edges of the brackets are preferably rounded/curved;

[0022] (ii) the transition from chamber to bracket and from cylinder tobracket is preferably smooth and rounded off,

[0023] (iii) the proposed titanium or any material used is preferablyhighly polished in order to avoid bacterial accumulation/bacterialvegetation at the surface of the material; and

[0024] (iv) the top part of the guiding rail and the edges of theinterconnecting bar are rounded off.

DESCRIPTION OF THE INVENTION

[0025] The device of the invention is preferably used as a maxillofacialdistractor, an osteogenic device, or a bone conducing device for thealveolar bone. Before use, the device is preferably sterilized (orautoclaved).

[0026] The device of the invention preferably comprises at least 2brackets, for instance up to 3. More preferably, the device contains 2brackets. Preferably, one of the brackets is a translating, cranial(upper) bracket and the other a fixed, caudal (lower) bracket. For thepurpose of this invention, ‘translating’ is defined as being able tomove up and down relative to the distraction screw (viewed in thevertical plane). For the purpose of this invention, ‘fixed bracket’ isdefined as a bracket that is not moving up and down relative to thedistraction screw during distraction. Preferably, the distraction screwcan be turned relative to the fixed bracket.

[0027] Preferably, the brackets, the distraction screw, the lateral pinsand the guiding rails (if present) and the interconnecting bars (ifpresent) are made of biocompatible materials, such as metals, polymers,and mixtures thereof. Preferred examples are metals (steel, Titanium),metal alloys (Nickel-Titaniun, Cobalt-Chromium alloys,Cobalt-Chromium-Nickel, CrCoMo), and polylactides. The most preferredexample is Titanium. Titanium has extraordinary tissue compatibility. Inorder to improve the rigidity of the device, each of the brackets ispreferably made of one piece of material. Preferably, the material andedges of the entire device are smooth without sharp edges.

[0028] The device preferably has a length of smaller than 35 mm, morepreferably smaller than 30 mm, most preferably smaller than 25 mm, forinstance 20 mm, and preferably larger than 3 mm, more preferably largerthan 5 mm, most preferably larger than 8 mm, for instance 10 mm Thedevice preferably has a width smaller than 35 mm, more preferablysmaller than 30 mm, most preferably smaller than 25 mm, and preferablylarger than 1 mm, more preferably larger than 2 mm, most preferablylarger than 3 mm. The device preferably has a thickness smaller than 35mm, more preferably smaller than 30 mm, and preferably larger than 1 mm,more preferably larger than 2 mm, most preferably larger than 3 mm, forinstance between 5 and 10 mm.

[0029] Translating Bracket

[0030] The translating bracket preferably comprises a cylinder.Preferably, the cylinder is hollow. Preferably, the cylinder isinternally threaded. Preferably, the cylinder is located centrally(viewed in the sagittal or- transversal plane) of and anteriorly (viewedin the sagittal or transversal plane) to the translating bracket.Preferably, the length of the cylinder runs perpendicularly to the planeof the bracket and perpendicularly to the plane of the distractionscrew.

[0031] The inner diameter of the cylinder is preferably from 0.5 mm,more preferably from 1 mm, most preferably from 1.5 mm and preferably upto 7 mm, more preferably up to 6 mm, most preferably up to 5 mm, inparticularly preferably smaller than 4 mm, for example 2 mm. The heightof the cylinder is preferably from 0.2 mm, more preferably from 0.4 mm,most preferably from 0.6 mm, particularly larger than 0.8 mm andpreferably up to 10 mm, more preferably up to 8 mm, most preferably upto 6mm, for example 2.5 mm The width of the cylinder is preferably from1 mm, more preferably from 2 mm, most preferably from 3 mm, preferablyup to 25 mm, more preferably up to 20 mm, most preferably up to 15 mm,for example between 5 and 10. The thickness of the cylinder ispreferably smaller than 25 mm, more preferably smaller than 20 mm, mostpreferably smaller than 15 mm and preferably from 1 mm, more preferablyfrom 2 mm, most preferably from 3 mm, for instance between 5 and 10 mm.

[0032] The translating bracket may not comprise a perforation. However,it is preferred that the translating bracket comprises one or moreperforations. The perforations can be used for fixating the translatingbracket with lateral pins to the underlying alveolar (jaw) bone that isto be distracted (moved away from the underlying bone). Preferably, theperforations are positioned in the horizontal (transversal) plane of thetranslating bracket, and are preferably completely embedded in thebracket. Preferably, the lateral perforations are located perpendicularto the cylinder and perpendicular to the distraction screw and directedaway from the distraction screw in a sagittal or transversal plane.Preferably, the perforations are round. The perforations are preferablysmooth and not internally threaded. The perforations match the diameterof the lateral pins and preferably have a diameter of from 0.2 mm, morepreferably from 0.4 mm, most preferably from 0.6 mm, preferably up to 5mm, more preferably up to 4 mm, for instance 0.9 mm. The number ofperforations of the translating bracket to be used depends on the forcesthat are exercised on the. device during distraction, while, at the sametime, damage to the nearby anatomical structures has to be avoided.Preferably, the translating bracket contains at least one perforation,for instance up to 10, preferably up to 8, more preferably up to 6, mostpreferably up to 4, in particular up to 3, for example two or oneperforation. The perforations may be located on either side of (lateralto, viewed in a transversal or sagittal plane) the cylinder (ifpresent), on one side of the cylinder, superior or inferior to orposterior to the cylinder. Preferably, the thickness of the bracketaround the perforation is at least 0.1 mm, more preferably at least 0.2mm.

[0033] In a particular embodiment of the invention, the perforations areplaced in a line at an angle relative to the distraction screw. Thisembodiment can be used in regions where more retention for the bracketsis required. For instance, in the intermental region, the perforationsshould be multiple on either side and preferably under an angle relativeto the distraction screw in order to counteract the lingual tensionforces of the musculature on the inside of the mouth. Preferably, theangle is between 90 and 0 degrees, more preferably between 30 and 60degrees, for instance at 45 degrees.

[0034] The length of the translating bracket is preferably from 0.5 mm,more preferably from 1 mm, most preferably from 2 mm and preferably to30 mm, more preferably to 20 mm, most preferably to 15 mm, in particularup to 10 mm, for instance 3 mm. The translating bracket preferably has awidth of from 2 mm, more preferably from 3 mm, most preferably from 4mm, and preferably to 25 mm, more preferably to 20 mm, most preferablyto 18 mm, in particular to 15 mm, for instance from 5 mm to 10 mm. Thethickness (including the cylinder) is preferably larger than 1 mm, morepreferably larger than 2 mm, most preferably larger than 2 mm, and inparticular larger than 3 mm, and preferably up to 25 mm, more preferablyup to 20 mm, most preferably up to 15 mm, for instance from 5 mm to 10mm.

[0035] Fixed Bracket

[0036] Preferably, the fixed bracket comprises one or more (2, 3 or 4)chambers. More preferably, the device comprises one chamber. One or moreof the chambers may-be solid. Preferably, one chamber comprises anaperture. The aperture can be in the shape of a cavity. Preferably, theaperture is a hollow tube. More preferably the aperture is a cylinder.Preferably, the chamber is in the shape of a cylinder. This facilitateseasy surgical fixation and removal of the device and allows forexchange, of the distraction screw during activation of the device.

[0037] The aperture in the chamber may have different widths atdifferent distances from the chamber surface. For instance, the aperturein the chamber may be wider (indentation) or narrower (extension) insidethe chamber as compared to the opening in the surface of the chamber.

[0038] Preferably, the diameter of cylindrical aperture in the chamberis from 0.5 mm, more preferably from 1 mm, most preferably from 1.5 mm,preferably up to 7 mm, more preferably up to 6 mm, most preferably up to5 mm, in particularly preferably smaller than 4 mm, for instance 2 mm.Preferably, the length of the cylindrically shaped aperture is largerthan 0.2 mm, more preferably larger than 0.5 mm, most preferably largerthan 0.8 mm and preferably smaller than 25 mm, more preferably smallerthan 20 mm, most preferably smaller than 15 mm, for instance 2 or 3 mm.

[0039] In a preferred embodiment of the invention, the chamber has anaperture at the top. The bottom of the aperture may be open (i.e. thechamber is perforated) or it may be solid (i.e. the chamber is notperforated). The aperture allows the distraction screw to be insertedand turned freely. If present, the bottom of the aperture could be flat,but is preferably V-shaped. The inner surface of the chamber is smoothand not threaded. In this embodiment, the aperture is preferablycylindrically shaped.

[0040] The length of the chamber is preferably larger than 0.2 mm, morepreferably larger than 0.4 mm, most preferably larger than 0.6 mm,particularly larger than 0.8 mm and preferably up to 20 mm, morepreferably to 10 mm, most preferably to 8 mm, for instance 2.5 mm. Thewidth of the chamber is preferably from 1 mm, more preferably from 2 mm,most preferably from 3 mm, preferably up to 25 mm, more preferably up to20 mm, most preferably up to 15 mm, for example between 5 and 10. Thechamber preferably has a thickness smaller than 25 mm, more preferablysmaller than 20 mm, most preferably smaller than 15 mm and preferablyfrom 1 mm, more preferably from 2 mm, most preferably from 3 mm, forinstance between 5 and 10 mm.

[0041] The fixed bracket may not comprise a perforation. However, it ispreferred that the fixed bracket comprises one or more perforations. Theperforations can be used for fixating the fixed bracket to theunderlying alveolar (jaw) bone with lateral pins. Preferably, theperforations are positioned in the horizontal (sagittally ortransversally in the fixed bracket) plane of the fixed bracket, and arepreferably completely embedded in the brackets. Preferably, theperforations are round. The perforations are preferably smooth and notinternally threaded. The perforations match the diameter of the lateralpins and preferably have a diameter of from 0.2 mm, more preferably from0.4 mm, most preferably from 0.6 mm, preferably up to 5 mm, morepreferably up to 4 mm, for instance 0.9 mm. The number of perforationsof the fixed bracket to be used depends on the forces that are exertedon the device during distraction, while, at the same time, damage to thenearby anatomical structures needs to be avoided. Preferably, the fixedbracket contains at least one perforation, for instance up to 10,preferably up to 8, more preferably up to 6, most preferably up to 4, inparticular up to 3, for example 2 or one perforation. The perforationsmay be located on either side of the chamber (if present), on one sideof the chamber, or posterior to the chamber. Preferably, the thicknessof the bracket around the perforation is at least 0.1 mm, morepreferably at least 0.2 mm.

[0042] In a particular embodiment of the invention, the perforations areplaced in a line at an angle relative to the distraction screw, in asagittal or transversal plane relative to the distraction screw. Thisembodiment can be used in regions where more retention for the bracketsis required. For instance, in the intermental region, the perforationsshould be multiple on either side and preferably under an angle relativeto the distraction screw in order to counteract the lingual tensionforces of the musculature on the inside of the mouth. Preferably, theangle is between 90 and 0 degrees, more preferably between 30 and 60degrees, for instance at 45 degrees.

[0043] The length of the fixed bracket is preferably from 0.5 mm, morepreferably from 1 mm, most preferably from 2 mm and preferably to 30 mm,more preferably to 20 mm, most preferably to 15 mm, in particular up to10 mm, for instance 3 mm. The fixed bracket preferably has a width offrom 2 mm, more preferably from 3 mm, most preferably from 4 mm, inparticular from 25 mm, and preferably to 20 mm, more preferably to 18mm, particularly preferred to 15 mm, for instance 10 mm. The thickness(including the chamber) is preferably larger than 1 mm, more preferablylarger than 2 mm, most preferably larger than 3 mm, and preferably up to25 mm, more preferably up to 20 mm, most preferably up to 15 mm, forinstance from 5 mm up to 10 mm.

[0044] Distraction Screw

[0045] Preferably, the device of the present invention comprises one ormore distraction screws. More preferably, the device comprises onedistraction screw. Preferably, the distraction screw comprises a head, ashaft and a tip.

[0046] The length of the distraction screw may vary depending on therequired distraction. Preferably, the length of the screw is up to 35mm, more preferably up to 30 mm, most preferably up to 25 mm, forinstance 20 mm, and preferably larger than 3 mm, more preferably largerthan 5 mm, most preferably larger than 8 mm, for instance 10 mm.

[0047] Preferably, the head of the distraction screw has a groove (onegroove or an “astrix” insertion). Preferably, the groove covers theentire diameter of the head. The circumference of the head is preferablyhexagonally shaped, more preferably in all planes. In order to enablethe surgeon or patient to easily read the distance of distraction afterhaving turned the distraction screw, the head of the distraction screwis preferably marked on the surface between the center and the side ofthe screw. The mark may be an indentation in the screw and/or mayconsist of a different color.

[0048] Preferably the shaft of the distraction screw is threaded.Preferably, the pitch of the thread is larger than 0.1 mm, morepreferably larger than 0.15 mm, most preferably larger than 0.2 mm, andpreferably smaller than 4 mm, more preferably smaller than 3 mm, mostpreferably smaller than 2.5 mm Examples of a pitch are 0.25 mm, 0.3 mm,0.5 mm, 1 mm, 1.5 mm and 2 mm. Preferably, the diameter of the shaft issmaller than 7 mm, more preferably smaller than 6 mm, most preferablysmaller than 5 mm, in particularly preferably smaller than 4 mm,preferably larger than 0.5 mm more preferably larger than 1 mm, mostpreferably larger than 1.5 mm, for instance 2 mm.

[0049] Preferably, the distraction screw is straight. Preferably, theshaft has one or more extensions and/or indentations, most preferablyone indentation. The extensions or indentations may be circular and/orlateral. They preferably have a smooth surface. Preferably, theextension or indentation extends along the length of the distractionscrew to the tip. The diameter of extensions may be at least 0.5 mmlarger than the diameter of the shaft, more preferably at least 1 mm,most preferably at least 2 mm, and preferably at most 20 mm, morepreferably at most 16 mm. The diameter of indentations may be at least0.1 mm smaller than the diameter of the shaft, more preferably at least0.2 mm, and preferably at most 3 mm, more preferably at most 2 mm.Preferably, the length of the extension and/or indentation matches thechamber of the fixed bracket and is preferably larger than 0.2 mm, morepreferably larger than 0.5 mm, most preferably larger than 0.8 mm andpreferably smaller than 25 mm, more preferably smaller than 20 mm, mostpreferably smaller than 15 mm, for instance 2 or 3 mm. Preferably, thediameter of extensions and/or indentations matches the aperture in thechamber and is preferably from 0.5 mm, more preferably from 1 mm, mostpreferably from 1.5 mm, preferably up to 7 mm, more preferably up to 6mm, most preferably up to 5 mm, in particularly preferably smaller than4 mm, for instance 2 mm.

[0050] The tip of the distraction screw may be flat, spherical orV-shaped. If V-shaped, the distraction screw may have a smooth andpolished tip.

[0051] Lateral Pin

[0052] The brackets can be glued on or adhered to the underlyinganatomic structures. However, to be able to withstand larger forces, thebrackets are preferably connected through lateral pins. Preferably, thepins are threaded. The pins may vary in length depending on thethickness of the underlying alveolar (jaw) bone, but are preferably from2 mm, more preferably 3 mm, most preferably 4 mm, preferably up to 20mm, more preferably 10 mm, most preferably up to 8 mm, particularly upto 6 mm in length The diameter of the pins-is preferably from 0.2 mm,more preferably from 0.4 mm, most preferably from 0.6 mm, preferably upto 5 mm, more preferably up to 4 mm, for instance 0.9 mm.

[0053] Preferably, the head of the lateral pin has a groove. Preferably,the groove covers the entire diameter of the ad.

[0054] Preferably, the pitch of the threads of the lateral pins islarger than 0.1 mm, more preferably larger than 0.15 mm, most preferablylarger than 0.2 mm, and preferably smaller than 4 mm, more preferablysmaller than 3 mm, most preferably smaller than 2.5 mm. Examples of apitch are 0.25 mm, 0.3 mm, 0.5 mm, 1 mm, 1.5 mm and 2 mm.

[0055] The pins have a tip for screwing into the bone. This is the onlypart of the device that has a sharp edge. However, this tip is notexposed to the soft tissue of the mouth. Therefore, devices of thepresent invention preferably contain no sharp edges that are in contactwith the mouth. Preferably, the only sharp element of the device of theinvention is the tip of the lateral pins.

[0056] Guiding Rail

[0057] Optionally, one or more of the brackets comprise one or moreguiding rails. If present, the guiding rail is preferably connected tothe fixed bracket. If present, the guiding rail can be attached to thebracket but is preferably continuous with the bracket, i.e. the bracketand the guiding rail are made from one piece of material. Preferably,the guiding rail has a smooth and polished surface.

[0058] If present, the guiding rail is preferably connected at theposterior (back) part of the bracket, although the guiding rail(s) mayalso be connected elsewhere.

[0059] In order to prevent the guiding rail from sticking out anddamaging the anatomical structures in the mouth, the guiding rail ispreferably shorter than the distraction screw. Preferably, the guidingrails has a length of smaller than 35 mm, more preferably smaller than30 mm, most preferably smaller than 25 mm and preferably up from 3 mm,more preferably up from 5 mm, most preferably up from 8 mm, for instancefrom 15 to 20 mm.

[0060] Preferably the guiding rail has a width of from 0.1 mm, morepreferably from 0.5 mm and preferably up to 6 mm, more preferably up to5 mm, most preferably up to 4 mm, for instance 3 mm. Preferably theguiding rail has a thickness of from 0.1 mm, more preferably 0.5 mm andpreferably up to 3 mm, more preferably up to 2 mm, most preferably up to1.5 mm for instance 1 mm.

[0061] If 2 or more guiding rails are present, then the guiding railsare preferably not connected with a bar. Such a device would increasethe size of the distractor and potentially lead to complications.

[0062] Interconnecting Bar

[0063] In certain cases, two or more distractors may be indicated, forinstance to move larger osteotomized (cut) bone. The use of biggerdistractors would increase the chance of infections. Also, biggerdistractors are less likely to be tolerated by the patient. To assureparallel movement of the two or more pieces of alveolar bone, aninterconnecting bar between two brackets may be used. A gradualdistraction over a long trajectory with two or more distractors ispreferred over distraction with a single large distractor.

[0064] Therefore, an embodiment of the present invention relates to 2 ormore (up to 3, preferably 2) devices with one or more (up to 2;preferably 1) of the brackets connected to the brackets of anotherdistractor by way of one or more (preferably 1) interconnecting bars.Preferably, a guiding rail is used for this embodiment of the invention.The lateral perforations through each of the brackets may be situatedwithin the interconnecting bar.

[0065] Positioning of the Parts of the Distractor

[0066] Preferably the device comprises brackets, and a distractionscrew. Preferably, the distraction screw runs perpendicularly throughthe cylinder on the translating bracket. Preferably, the screw can turnin the thread of the cylinder of the translating bracket. Preferably,the distraction screw rests on and slots into (preferably a smooth areaof) the fixed bracket after placement by the surgeon. By turning thedistraction screw, the screw will push against the fixed bracket andmove the translating bracket along the thread of the distraction screw.

[0067] In order to reduce the size of the device and improve thestability, the chamber of the fixed bracket is preferably locatedentirely on one side (for instance below) of the cylinder of thetranslating bracket (in the vertical plane relative to the cylinder).Preferably, the cylinder of the translating bracket is located (viewedin the vertical and/or sagittal view) entirely outside (and preferablyon one side) of the chamber of the fixed bracket. The chamber of thefixed bracket and the rest of the fixed bracket (that comprises at leastpart of any perforations) are preferably located on the same side(viewed in a sagittal or transversal plane) of the translating bracket.Thus, the chamber of the fixed bracket does not extend to the other sideof the cylinder of the translating bracket.

[0068] Preferably, the distraction screw rests on the surface of thefixed bracket. Preferably, the distraction screw slots into the apertureof the fixed bracket with an extension and/or an indentation.Preferably, the distraction screw rests against the surface of the fixedbracket on the side facing the translating bracket. Preferably, thissurface is part of the chamber of the fixed bracket. The surface can,for instance, be the outer surface of the chamber on fixed bracketand/or the bottom of the aperture in the chamber. Preferably, the bottomof the aperture, if present, matches the shape of the tip of thedistraction screw.

[0069] As indicated above, the shaft of the distraction screw mayoptionally have one or more extensions (for instance circular andlateral) and/or one or more indentations (for instance circular andlateral). These may be positioned at one or more locations towardsand/or at the tip of the distraction screw.

[0070] The distraction screw is preferably positioned in the aperture ofthe fixed bracket. Lateral extensions and or indentations of thedistraction screw may rest against the surface of the fixed bracket.Extensions and/or indentations of the distraction screw may also bepositioned inside the fixed bracket and match with indentations and/orextensions of the aperture of the fixed bracket. Such extensions andindentations may prevent the distraction screw from moving out orthrough (up and down; in the vertical plane) the fixed bracket. Use ofthese extensions or indentations may stabilize the distraction screwrelative to the fixed bracket and make the connection between the fixedbracket and the distraction screw tighter (rigid/robust).

[0071] In a preferred embodiment of the invention, the chamber of thefixed bracket has an aperture on the surface at the side facing thetranslating bracket. The aperture extends into the chamber. The bottomof the aperture is solid and not perforated on the other side of thechamber. The distraction screw is inserted and turned freely in theaperture of the fixed bracket. Preferably, the distraction screw restson the bottom of the aperture and/or on the outer surface of the fixedbracket (for instance through a lateral extension that might becircular, as discussed above). The distraction screw can be inserted inthe fixed bracket, for instance for a distance from 0.5 mm to 3 mm, maystabilize the distraction screw relative to the fixed bracket and makethe connection between the fixed bracket and the distraction screwtighter (rigid/robust).

[0072] In an especially preferred embodiment of the invention, thedistraction screw does not have extensions inside in the aperture of thechamber of the fixed bracket. This allows the distraction screw to beremoved from the fixed bracket through the aperture at the top and fromthe translating bracket. This preferred embodiment allows the surgeon toreplace the distraction screw, for instance with a longer distractionscrew, during the process of distraction and without unscrewing thebrackets from the underlying bone.

[0073] Preferably, the device of the invention does not interfere withthe site of osteogenesis. It is therefore preferred that the brackets donot have extensions that are directed perpendicularly to the distractionscrew and/or perpendicularly to the brackets, at a level between thebrackets and directed away from the distraction screw into the site ofosteogenesis (viewed in a sagittal or transversal plane). Preferably,the distraction screw is not present in the site of osteogenesis.Preferably, the lateral pins are located perpendicularly to thedistraction screw and preferably perpendicularly to the brackets andpreferably directed away (sagitally or transversally) from thedistraction screw into the bone. To improve the healing process, thelateral pins do preferably not interfere with the site ofneo-osteogenesis and preferably do not damage the surrounding anatomicalstructures. Preferably, perforations (preferably embedded) on the fixedbracket and/or on the translating bracket face away from the distractionscrew viewed in a vertical (sagittal or transversal) plane.

[0074] The optional guiding rail slides through the opposing bracket.For instance, if connected to the fixed bracket, it slides through thetranslating bracket, or visa versa. The rail guides the brackets in theright direction and makes the connection tighter (rigid/robust).

[0075] If present, the guiding rail is most preferably connected at theposterior (back) part of the bracket, posterior to the distraction screwand parallel to the distraction screw. However, the guiding rail(s) mayalso be connected elsewhere, for instance around the distraction screw.The guiding rail may also be placed parallel and adjacent, for instanceon the sides or in the front of the distraction screw (when viewed in asagittal or transversal plane). If placed in the front (anteriorly), theguiding rail will also protect the anatomical structures from beingexposed to the distraction screw.

[0076] The Lateral Pins may vary in length and may be used either formonocortical or bicortical fixation.

[0077] Manufacture of the Device

[0078] The device of the present invention is preferably manufactured bypreparing the translating bracket with a cylinder, the fixed bracket andthe distraction screw, and turning the distraction screw through thecylinder of the translating bracket. Preferably, the device compriseslateral pins.

[0079] Preferably the parts of the device of the present invention aremanufactured without using-welding or soldered connections. Instead eachpart is preferably manufactured out of one solid piece through casting.Therefore, preferably the distraction screw is manufactured out of onepiece, preferably the translating bracket is manufactured out of onepiece, and preferably the fixed bracket is manufactured out of onepiece.

[0080] Distraction Process

[0081] In edentulous patients (those who have no dentition)3-dimensional resorption and atrophy has affected both the mandible(lower jaw), maxilla (upper jaw) and the soft tissues of the face. Thecortical (outer) surface of the mandible is in those patients(classified as Cawood IV, V and VI) mostly remodeled to a convex pipebone. In contrast the maxilla is in case of Cawood IV, V and VIclassification mostly resorbed to an alveolar (jaw) crest shaped like aknife-edge with a concave cortical (outer) surface. In order to performa successful vertical distraction histio-osteogenesis the appropriateattachment of the distractor to the resorbed alveolar (jaw) bone isessential. Considering the configuration and dimensions of the resorbedand atrophied mandible, the device of the present invention offersadvantages above the distractors of the prior art.

[0082] The brackets of the device of the present invention enables thesurgeon to position the distractor accurately without damaging theadjacent anatomical structures. Some devices of the prior art requirebending or cutting the micro plates for adaptation in e.g. alveolardistraction of single diasthemas (gap resulting from the removal of atooth). In the device of the present invention, the construction of thebrackets is preferably rigid and manufactured out of one piece and ispreferably not soldered, as is the case in many devices of the priorart.

[0083] In the device of the present invention, the brackets arepositioned on the buccal (outside) surface (extra cortical) of thealveolar (jaw) bone and do not interfere with the neo-osteogenic (newlygrown bone) site. However in the design of devices of the prior art,elements (for instance the microplates) are bent to and lie within theneo-osteogenic (newly grown bone) gap and interfere with the augmentedbone. Therefore removal of the microplates after completion ofdistraction osteogenesis does not contribute to the stability of thenewly distracted layer of bone and will lead to unpredictable results.

[0084] The device as proposed may be applied in the entire orofacialskeleton in order to s lengthen and augment the jaws vertically and/orhorizontally. The device of the present invention is preferably used forvertical osteogenesis through distraction. Preferably, the device of thepresent invention is used for distraction of a piece of bone from thejaw.

[0085] The device of the invention can be used for distraction of asingle tooth defect. The device can also be used for distraction of aresorbed alveolar ridge. The osteotomies can be made and themicrodistractors can be fixated to the mandible.

[0086] The device is preferably sterilized in an autoclave before use.Therefore the device is preferably autoclaved.

[0087] A further embodiment of the invention relates to a method ofdistracting two segments of bone using the device of the presentinvention. Preferably, the fixed bracket is connected to one segment ofbone and the translating bracket is connected to the other segment ofbone that is to be distracted away from the other segment of bone.Preferably, the distraction screw is inserted through the cylinder ofthe translating bracket and placed on (and preferably slotted into) thechamber of the fixed bracket. By turning the distraction screw, the twosegments of bone are distracted.

[0088] Preferably, the segment of bone that is to be distracted is cut(osteomized) from the underlying jaw and the translating bracket isattached thereto. Preferably, the fixed bracket is attached to theunderlying bone, for instance the jaw.

[0089] After placement of the device of the invention in the jaw of apatient, the device is preferably left for a period of 3 to 7 days.After this period, the translating bracket scan be moved up by 0.5 to1.0 mm per day. Preferably, the distraction ranges from a 2 mm to anextreme of 5 mm, more preferably from 5 mm to 30 mm, most. preferably upto 20 mm.

[0090] Preferably, the entire distractor lies underneath themucoperiosteal layer and will be activated one week after insertion,i.e. when healing of the tissues have commenced. The device is enwrappedin a soft tissue envelope (mucoperiost). This is a subperiosteal(submucosal) fixation. Hardly any friction is possible which preventfraction of the device and the underlying pieces of bone.

[0091] The distracted bone may for instance enable placement of a dentalimplant.

[0092] It has to be understood that all dimensions mentioned in theapplication should preferably be interpreted as being about the sizeindicated. In this respect it is particularly preferred that the purposeof that aspect of the invention is taken into account.

FIGURES

[0093]FIG. 1 presents a translating bracket (1) with perforations (7)and with a cylinder (4) with an internal diameter (8) and a thread (9)internally. FIG. 2 presents a fixed bracket (2) with perforations (7)and a chamber (5) that comprises an internal cylindrical aperture (10).FIG. 3 presents a fixed bracket (2) with perforations (7), a chamber (5)with an aperture (10) and with a guiding rail (6). FIG. 4 presents afixed bracket (2) with a chamber (5) with an aperture (10) and with theline of the perforations (7) under an angle a of about 45 degrees. FIG.5 presents an example of the chamber (S) where the chamber is piercedthrough (11) with a cylindrically shaped aperture (10). FIG. 6 is achamber (5) with a cylindrically shaped aperture (10) that onlypartially pierces the chamber and wherein the bottom of the cylinder isflat (12). FIG. 7 presents a chamber (5) where the aperture (10)converges at the apex (13). The aperture does not entirely pierce thechamber (5). FIG. 8 presents a distraction screw (3) with a head (14), athreaded shaft (15), and a non-threaded tip (16). FIG. 9 presents adistraction screw with two indentations (16) and (16), an “apicalshoulder”. FIG. 10 presents an osteosynthetic pin (17). FIG. 11 presentsa device with a guiding rail in situ and FIG. 12 presents an explodedview of the device seen in FIG. 11. FIG. 13 presents a device without aguiding rail and FIG. 14 presents an exploded view of the device.

EXAMPLES Example 1

[0094] A device was manufactured with the following characteristics. Thetranslating bracket comprises a cylinder, 2 perforations and 2 pins thatmatch the perforations. The cylinder has an internal thread. Thecylinder is located centrally (viewed in the frontal plane) of andanteriorly (viewed in the sagittal plane) to the translating bracket.The length of the cylinder runs perpendicularly to the plane of thebracket and perpendicularly to the plane of the distraction screw. Theinner diameter of the cylinder is 2.0 mm, the thickness of the cylinderwall is 1.5 mm and the height of the cylinder is 3.0 mm.

[0095] The translating bracket comprises 2 perforations. Theperforations are positioned in the horizontal to (viewed in a sagittalor transversal plane) the translating bracket, and are completelyembedded in the bracket. The perforations are round, smooth and notinternally threaded. The perforations match the diameter of the lateralpins and have a diameter of 0.9 mm. The perforations are located oneither side of the cylinder. The thickness of the bracket around theperforation is 3.0 mm. The line of the perforations in the translatingbracket is 90 degrees relative to the distraction screw, but might beplaced at an angle of 45 degrees at an angle if more retention isrequired. The translating bracket has a width of smaller than 10 mm, alength of about 5 mm, and a thickness (including the cylinder) of about5 mm.

[0096] The fixed bracket comprises one chamber with an aperture in theshape of a hollow cylinder. The diameter of the aperture in the chamberis 1.9 mm. The chamber has an aperture at the top, while the bottom ofthe aperture is solid and not perforated. The open top and the closedbottom of the aperture, together, allow the distraction screw to beinserted and turned freely. The bottom of the aperture is flat. Theinner surface of the chamber is smooth and not threaded. The length ofthe cylindrically shaped aperture is 1.2 mm.

[0097] The length of the chamber is about 2.5 mm. The width of thechamber is about 4 mm. The chamber has a thickness of about 5 mm. Thefixed bracket comprises 2 perforations on either side of the chamber.The perforations are positioned in the horizontal to (viewed in asagittal or transversal plane) the fixed bracket and are completelyembedded in the brackets. The perforations are round, smooth and notinternally threaded. The perforations match the diameter of the lateralpins and have a diameter of about 0.9 mm.

[0098] The fixed bracket has the same dimensions as the translatingbracket.

[0099] The device comprises one distraction screw with a head, a shaftand a tip. The length of the distraction screw is 20 mm. The head of thedistraction screw has a groove. The groove covers the entire diameter ofthe head. The circumference of the head is hexagonally shaped. In orderto enable the surgeon or patient to easily read the distance ofdistraction after having turned the distraction screw, the head of thedistraction screw is marked on the surface between the center and theside of the screw. The mark may be a colored indentation in the screw.

[0100] The shaft of the distraction screw is threaded. The pitch of thethread is 0.25 mm The diameter of the shaft is 1.9 mm. The distractionscrew is straight and does not have any extensions or indentations. Thetip of the distraction screw is flat, smooth and polished tip. Thelateral pins are threaded and are 4 mm in length with a diameter of 0.9mm. The head of the lateral pin has a groove covering the entirediameter of the head. The pitch of the threads of the lateral pins isabout 0.9 mm.

[0101] The device comprises a guiding rail continuously with the fixedbracket and made from one piece of Titanium with a smooth and polishedsurface. It is connected at the posterior (back) part of the fixedbracket and has a rounded top. The guiding rail has a length just shortof the distraction screw. The guiding rail has a width of 3 mm. Theguiding rail has a thickness of 1 mm.

[0102] The device does not have an interconnecting bar.

[0103] The distraction screw runs perpendicularly through the cylinderon the translating bracket. The screw turns in thread of the cylinder ofthe translating bracket. The distraction screw rests on the fixedbracket. By turning the distraction screw, the screw will push againstthe fixed bracket and move the translating bracket along the thread ofthe distraction screw.

[0104] The chamber of the fixed bracket is located entirely on one sideof the cylinder of the translating bracket (when viewed in a sagittal ortransversal plane). The cylinder of the translating bracket is locatedentirely outside of the chamber of the fixed bracket. The chamber of thefixed bracket and the rest of the fixed bracket are located on the sameside of the translating bracket. Thus, the chamber of the fixed bracketdoes not extend to the other side of the cylinder of the translatingbracket. The distraction screw rests on the bottom of the aperture inthe chamber.

[0105] The distraction screw is inserted and turned freely in theaperture of the fixed bracket. The distraction screw rests on the bottomof the aperture. The distraction screw is inserted in the fixed bracketfor about 1.5 mm.

[0106] The distraction screw does not have extensions inside in theaperture of the chamber of the fixed bracket. This allows thedistraction screw to be removed from the fixed bracket through theaperture at the top and from the translating bracket (for instance to beexchanged for a shorter or preferably a longer screw). This allows thesurgeon to replace the distraction screw, for instance with a longerdistraction screw, during the process of distraction and withoutunscrewing the brackets from the underlying bone.

[0107] The device of the invention does not interfere with the site ofneo-osteogenesis. The brackets do not have extensions that are directedperpendicularly to the distraction screw and perpendicularly to thebrackets, at a level between the brackets and directed away from thedistraction screw into the site of neo-osteogenesis. Also, thedistraction screw is not present in the site of neo-osteogenesis whichis away from the distraction screw viewed in a sagittal or transversalplane.

[0108] The lateral pins are located perpendicularly to the distractionscrew and perpendicularly to the brackets (viewed in a sagittal ortransversal plane). The lateral pins have a length of about 4 mm. Thelateral pins do not interfere with the site of neo-osteogenesis and donot damage the surrounding anatomical structures. The guiding railslides through the translating bracket.

[0109] The guiding rail is connected at the posterior (back) part of thebracket, posterior to the distraction screw and parallel to thedistraction screw.

[0110] The device is activated by turning the distraction screw throughthe cylinder of the translating bracket and onto the fixed bracket ontoor into the chamber, alongside the guiding rail, after fixation of thedevice by the lateral pins. The parts of the device are manufacturedwithout using welding or soldered connections. Instead each part ismanufactured out of one solid piece through casting.

[0111] We simulated the distraction process on a plexiglass modelresembling the anatomical sizes of a human mandible. The device wasapplied in the mandible and maxillain order to distract the jawvertically.

[0112] One piece of plastic of the model was distracted using thedevice. The translated bracket is connected to the osteotomized mandiblepiece to be distracted-and-that was cut from the underlying model. Thefixed bracket was attached to the underlying mandible, the piece not tobe distracted. The distraction screw is inserted through the cylinder ofthe translating bracket and placed on the chamber of the fixed bracket.By turning the distraction screw, the piece is distracted for 20 mm. Thesame was done for the maxilla, instead of the mandible.

[0113] The vertical upward movement of the translating bracket followswithout difficulty and the fixated cranial (upper) part of the mandiblecan be lifted in a controlled fashion. The rigidity of the device issatisfying considering the absence of soft tissues on the model. It isnot possible to bend or distort the device by digital tension force.

Example 2

[0114] A second device is manufactured. This device is the same as thefirst device, but without the guiding rail. Again the device distracteda piece of the model for 20 mm.

Example 3

[0115] A third device was manufactured. This device is half the size ofthe second device, apart from the length of the distraction screw, whichwas also 20 mm Again the device distracted a piece (part) of the modelfor 20 mm. When distracted at a length of 20 mm, a device with guidingrail is more stable and shows less torque. A device without guiding railshows neither distortion nor bending at digital pressure in a mandibularmodel. While absent in the mandibular model, in the patient's mouth theperiosteum and musculo-mucosal envelope would give additional rigidityand buccal tension to the device, likely to prevent the aforementionedslight transverse movement at maximum distraction length of 20 mm. Thedevice was successfully tested in vitro. The design of the device takesinto consideration the (specific) anatomical dimensions of the resorbedand atrophied mandible.

Example 4

[0116] A 29-year-old male with an anterior mandibular defect was treatedby distraction histio-osteogenesis. Pre-operative planning was performedby measuring and assessing the clinical defect, plater models, anorthopantomogram and lateral skull X-ray. Prior to incision the outlayof incisions and lines of osteotomy were drawn onto the mucosa. A deviceaccording to the invention as described in Example 1 was placed toassess its position in the (i) vertical (ii) transversal (iii) sagittalplane and (iv) to check its interference with the occlusal plane.Hereafter—using a microtome or microsaw—an osteotomy is performed. Thefollowing considerations to the osteotomy were given:

[0117] 1. performance of a bicortical osteotomy

[0118] 2. preferably at least 3-5 mm away from adjacent teeth

[0119] 3. the vertical and horizontal lines of osteotomy are preferablyconnected using rounded angles

[0120] 4. after completion of the osteotomy, the free segment could bemobilized from its underlying bone in 3 dimensions.

[0121] During the surgical procedure a microdistractor as described inthis patent was used. Firstly the fixed bracket containing the guidingrail was fixed to the underlying alveolar bone in the midline of themandibular defect. Fixation of the fixed bracket took place using 4osteosynthetic pins of 7 mm in length. Hereafter the translating bracketwas placed just above the line of osteotomy and in a vertical planerelative to the fixed bracket. The translating bracket was fixed with 4osteosynthetic pins of 7 mm in length. Subsequently a distraction screwwith a length of 20 mm was inserted through the cylinder of thetranslating bracket and resting on and slotting into chamber of thefixed bracket. During the surgical procedure the device was activated toapproximately half of its length to simulate and anticipate the clinicaldistraction. The distraction screw was then returned by screwing back toits starting position to the point where the cranial and caudal osseous(bony) segments made contact. The vulnerae (wounds) were closed with anuninterrupted 4-0 Vicryl sutures. The head of the distractor was theonly part allowed to protrude transmucosally. In order to protect theadjacent soft tissues of the oral cavity the head of the distractionscrew was covered by a silastic tube. Post-operative the patient wasgiven a chin bandage for support of the mental bandage. Fixation of thedevice was performed by (i) placing the fixed bracket at least 3-5 mmaway from the line of osteotomy (ii) placing the translating bracket atleast 3-5 mm away b the line of osteotomy (iii) assuring that thedistraction screw translates the segment in a satisfactory manner in 3planes.

[0122] The device was activated to preview the transport until themoment that blanching of the soft tissues occurred. At this point thedevice was turned back until the point that both osseous segments madecontact. The mucoperiosteum was closed in an uninterrupted fashion with4-0 Vicryl sutures. Upon completion of the surgical procedure the headof the distraction screw was covered by a rubber or silastic hollow tubeto protect the surrounding oral tissues. Activation commenced between3-7 days post-operatively. The rate of activation was between 0.2-1.0 mmper day. After 2 weeks of activation, the device had created 10 mm ofnew alveolar bone, which was used for a dental implant.

1. Vertical alveolar osteogenesis microdistractor device comprising atranslating bracket (1) with a cylinder (4), a fixed bracket (2) with achamber (5) with an aperture (10), a distraction screw (3), lateral pins(17) for fixating the translating and fixed brackets (1, 2) to anunderlying bone, and a guiding rail (6) connecting the brackets (1, 2)and extending posterior and parallel to the distraction screw (3),wherein the aperture (10) is smooth and not threaded, wherein thedistraction screw (3) is turned through the cylinder (4) of thetranslating bracket (1) and placed into the aperture (10) of the chamber(5) of the fixed bracket (2), the aperture (10) of the chamber (5) beingadapted to allow the distraction screw (3) to be inserted and turnedfreely in the chamber (5), the distraction screw (3) being shaped suchas to allow its removal from the fixed bracket (2) through the aperture(10) and from the translating bracket (1), wherein the chamber (5) ofthe fixed bracket (2) and the rest of the fixed bracket (2) are locatedat a single side of the translating bracket (1), and wherein thedistraction screw (3), the cylinder (4), and the chamber (5) are locatedat a single side of a surface defined by the brackets (1, 2) and theguiding rail (6) in the assembled state of the device, such that thedistraction screw (3), the cylinder (4), and the chamber (5) do notinterfere with the osteogenesis site.
 2. Vertical alveolar osteogenesismicrodistractor device comprising a translating bracket (1) with acylinder (4), a fixed bracket (2) with a chamber (5) with an aperture(10), a distraction screw (3), lateral pins (17) for fixating thetranslating and fixed brackets (1, 2) to the underlying bone, and aguiding rail (6) connecting the brackets (1, 2) and extending posteriorand parallel to the distraction screw (3), wherein the aperture (10) issmooth and not threaded, wherein the distraction screw (3) is turnedthrough the cylinder (4) of the translating bracket (1) and placed intothe aperture (10) of the chamber (5) of the fixed bracket (2), whereinthe chamber (5) of the fixed bracket (2) and the rest of the fixedbracket (2) are located at a single side of the translating bracket (1),and wherein the distraction screw (3), the cylinder (4), and the chamber(5) are located at a single side of a surface defined by the brackets(1, 2) and the guiding rail (6) in the assembled state of the device,such that the distraction screw (3), the cylinder (4), and the chamber(5) do not interfere with the osteogenesis site.
 3. The verticalalveolar osteogenesis microdistractor device of claims 1 or 2 whereinthe chamber (5) of the fixed bracket (2) is a bottomed chamber.
 4. Thevertical alveolar osteogenesis microdistractor device of one or more ofclaims 1-3 wherein the device is smooth and without sharp edges.
 5. Thevertical alveolar osteogenesis microdistractor device of one or more ofclaims 1-4 wherein the guiding rail (6) is integral with the fixedbracket (2) and slidable into the translating bracket (1).
 6. Thevertical alveolar osteogenesis microdistractor device of one or more ofclaims 1-4 wherein the guiding rail (6) is integral with the translatingbracket (1) and slidable into the fixed bracket (2).
 7. The verticalalveolar osteogenesis microdistractor device of one or more of claims1-6 wherein the tip of the distraction screw (3) is flat or spherical.8. The vertical alveolar osteogenesis microdistractor device of one ormore of claims 1-6 wherein the tip of the distraction screw (3) issmooth and polished.
 9. Method of vertical alveolar distraction of twobone pieces using a device comprising a translating bracket with acylinder, a fixed bracket with a chamber with an aperture, and adistraction screw wherein the fixed bracket is connect to one piece ofbone, the translating bracket is connected to the other piece of bone,the distraction screw is inserted through the cylinder of thetranslating bracket and placed in the aperture of the chamber of thefixed bracket, wherein the two pieces of bone are distracted by turningthe distraction screw, and wherein the device does not interfere withthe osteogenic side.